Aug. 19, 2010 -- People who add more green leafy vegetables to their diet may significantly reduce their risk of developing type 2 diabetes, a new study says.

Patrice Carter, a research nutritionist at the University of Leicester, and colleagues reviewed six studies involving more than 220,000 people that focused on the links between fruits and vegetables and type 2 diabetes.

They conclude that eating one and one half servings of green leafy vegetables per day reduces the risk of type 2 diabetes by 14%. However, they also found that eating more fruits and vegetables combined doesn't seem to affect this risk.

Fruit and Vegetable Intake

Although many studies have found that diets high in fruits and vegetables reduce the risk of heart disease and cancer, many people don't seem to be getting the message, researchers say.

For example:

86% of adults in the United Kingdom ate less than the recommended five servings of fruits and vegetables per day, according to a 2002 study.

62% ate fewer than three servings.

Eat More Vegetables

The authors say that fruits and vegetables can prevent several chronic diseases, likely because of their antioxidant content.

Spinach and other green leafy veggies may reduce type 2 diabetes risk because of their high concentrations of polyphenols and vitamin C, both of which have antioxidant properties. They also contain magnesium, which may further reduce risk.

They conclude that specific, tailored advice needs to be given to people to encourage them to eat more green leafy vegetables.

Another Perspective

Jim Mann, PhD, of the University of Otago in New Zealand, and research assistant Dagfinn Aune from Imperial College London say they are cautious about the results. They say the message of eating more fruits and vegetables should not get lost “in a plethora of magic bullets.”

They say that given the limited number of studies that focused on fruits, vegetables, and type 2 diabetes risk, “it may be too early to dismiss a small reduction in risk for overall fruit and vegetable intake or other specific types of fruits and vegetables, and too early for a conclusion regarding green leafy vegetables.”

But Carter and colleagues seem to be saying that it's better to err on the side of caution, and that some evidence suggests that green leafy vegetables reduce diabetes risk, even though “the exact mechanisms” are not known.

"The study adds to the evidence that a healthy lifestyle, and in particular green leafy vegetables, can help prevent type 2 diabetes," Carter tells WebMD.

The study is published in the BMJ, formerly known as the British Medical Journal.